This invention relates to radio-frequency (RF) receivers and transceivers. More particularly, the invention concerns (i) ways of partitioning high-performance RF receiver or transceiver circuitry into circuit partitions so as to reduce interference effects among the circuit partitions, and (ii) circuits and protocols that facilitate interfacing among the circuit partitions.
The proliferation and popularity of mobile radio and telephony applications has led to market demand for communication systems with low cost, low power, and small form-factor radio-frequency (RF) transceivers. As a result, recent research has focused on providing monolithic transceivers using low-cost complementary metal-oxide semiconductor (CMOS) technology. Current research has focused on providing an RF transceiver within a single integrated circuit (IC). For discussions of the research efforts and the issues surrounding the integration of RF transceivers, see Jacques C. Rudell et al., Recent Developments in High Integration Multi-Standard CMOS Transceivers for Personal Communication Systems, INVITED PAPER AT THE 1998 INTERNATIONAL SYMPOSIUM ON LOW POWER ELECTRONICS, MONTEREY, CALIFORNIA; Asad A. Abidi, CMOS Wireless Transceivers: The New Wave, IEEE COMMUNICATIONS MAG., August 1999, at 119; Jan Crols and Michael S. J. Steyaert, 45 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMSxe2x80x94II: ANALOG AND DIGITAL SIGNAL PROCESSING 269 (1998); and Jacques C. Rudell et al., A 1.9-GHz Wide-Band IF Double Conversion CMOS Receiver for Cordless Telephone Applications, 32 IEEE J. OF SOLID-STATE CIRCUITS 2071 (1997), all incorporated by reference here in their entireties.
The integration of transceiver circuits is not a trivial problem, as it must take into account the requirements of the transceiver""s circuitry and the communication standards governing the transceiver""s operation. From the perspective of the transceiver""s circuitry, RF transceivers typically include sensitive components susceptible to noise and interference with one another and with external sources. Integrating the transceiver""s circuitry into one integrated circuit would exacerbate interference among the various blocks of the transceiver""s circuitry. Moreover, communication standards governing RF transceiver operation outline a set of requirements for noise, inter-modulation, blocking performance, output power, and spectral emission of the transceiver. Unfortunately, no method for addressing all of the above issues in high-performance RF receivers or transceivers, for example, RF transceivers used in cellular and telephony applications, has been developed. A need therefore exists for techniques of partitioning and integrating RF receivers or transceivers that would provide low-cost, low form-factor RF transceivers for high-performance applications, for example, in cellular handsets.
This invention provides techniques for partitioning radio-frequency (RF) apparatus, for example, receivers or transceivers. In one embodiment, the RF apparatus comprises a first circuit partition that includes receiver analog circuitry that is configured to produce a digital receive signal from an analog radio-frequency signal. The RF apparatus also comprises a second circuit partition that includes receiver digital circuitry that is configured to accept the digital receive signal. The first and second circuit partitions are partitioned so that interference effects between the first circuit partition and the second circuit partition tend to be reduced.
In another embodiment, an RF transceiver according to the invention comprises a first circuit partition that includes receiver analog circuitry that is configured to accept a received RF signal and to provide at least one digital output signal. The first circuit partition also includes transmitter circuitry that is configured to receive at least one transmit input signal and to provide a transmit RF signal. The RF transceiver also comprises a second circuit partition that includes local-oscillator circuitry that is configured to accept a reference signal. The local oscillator circuitry is further configured to provide a radio-frequency (RF) signal to the receiver analog circuitry. The first circuit partition and the second circuit partition are partitioned so that interference effects between the first circuit partition and the second circuit partition tend to be reduced.
Another aspect of the invention relates to methods of partitioning RF apparatus, for example, receivers and transceivers. In one embodiment, the method includes providing a first circuit partition that comprises receiver analog circuitry, and utilizing the receiver analog circuitry to produce a digital receive signal from an analog RF signal. The method also includes providing a second circuit partition that comprises receiver digital circuitry, and utilizing the receiver digital circuitry to accept the digital receive signal. Finally, the method includes partitioning the first and second circuit partitions so that interference effects between the first circuit partition and the second circuit partition tend to be reduced.
In another embodiment, a method of partitioning an RF transceiver includes providing a first circuit partition that includes receiver analog circuitry and transmitter circuitry. The method further includes utilizing the receiver analog circuitry to accept a received RF signal and to provide at least one digital output signal, and utilizing the transmitter circuitry to receive at least one transmit input signal and to provide a transmit RF signal. The method also comprises providing a second circuit partition that includes local-oscillator circuitry, and utilizing the local-oscillator circuitry to accept a reference signal, and to provide a radio-frequency (RF) signal to the receiver analog circuitry. Finally, the method includes partitioning the first circuit partition and the second circuit partition so that interference effects between the first circuit partition and the second circuit partition tend to be reduced.